Nagra HD AMP

NAGRA HD AMP
Statement power amplifier

The Nagra HD AMP was designed for ultimate high-end systems that are able to reproduce the music realistically. The HD AMP are mono amplifiers, they can drive the most demanding speakers and transcend their performance.

The HD AMP came from the need of bringing Nagra signature transparency into more powerful amplifiers to accommodate yet larger rooms and larger speakers.

Features

It all started from our customers who could not use Nagra amplifiers, like the acclaimed Nagra MSA, in their bigger systems because they needed more power to accommodate demanding speakers or a very large room. They were frustrated to mix and match Nagra sources, such as the HD DAC, with other brands for amplification.

Early in the development stage, we realize that we could push the limits of what is possible to achieve in an amplifier, if we allowed ourselves to have a larger chassis. We took inspiration from the world-acclaimed Nagra VPA amplifier and designed elegant tower-shaped monoblocks.

The power supply goes to extremes to make sure the amplifier is stable and can deliver high power at any time. It is built around a 1600 VA transformer. In Nagra’s own tradition it is followed by a multiple diode stage and a very complex dual PI filter. This allows the amplifier voltage rails to be extremely stable. In addition, the current draw from the HD AMP is not polluted by impulse signals. So the rest of the set-up can perform at its best. The dual Pi filter acts like a protection shield between the HD AMP and the mains.

Each Nagra HD AMP unit features a bank of 264 mF of custom-made Mundorf condensers. They are the reference in their category and you rarely meet them in this quantity because most manufacturers consider them too expensive. We have chosen them after many hours on the test bench and numerous critical listening sessions.

The Nagra HD AMP audio amplification stage is relatively simple in its conception; this is in part what makes it so transparent and direct. Actually, each stage has been tuned to reach striking results. The driver stage for instance features numerous decoupling capacitors of different technologies. It has a very low output impedance to make the most of the power MOSFETs that follow.

Like all its famous predecessors in Nagra range, the HD AMP, uses MOSFET, field effect transistors. They are the closest thing to a valve triode and you can definitely feel its sonic character: direct, fast and musical. The HD AMP has precisely matched clusters of MOSFET, to insure the purest reproduction.

The Nagra HD AMP is fitted with a traditional Nagra Modulometer on the front panel, showing the output power.

An LED is also fitted to indicate saturations, excessive temperature.

The amplifier is equipped with balanced and unbalanced inputs and an IN/OUT trigger function.

Technical specifications

Electronics

Power

250 W RMS per channel into 8 Ω

30 W pure class A

1000 W RMS on lower impedance

Sensitivity

1 V or 2 V RMS

Bandwidth

0 Hz to 120 KHz, +0/-0.5 dB

Crosstalk

Not related for mono amplifiers

Signal-to-noise ratio

Typically 110 dB

ASA “A” weighted

THD+N

< 0.03%

Input type

XLR balanced

RCA unbalanced

Input impedance

88 KΩ on balanced input

t44 kΩ on unbalanced input

DC filter

Toggle switch allows to cut the DC of incoming signals

Protection,

Overheating > +70° C (158° F)

Remote in and out

1/8″ jacks in and out can trigger the amplifier on or off from a Nagra MPS or a home automation system